Then, when his unit was camped outside Benghazi, in Libya, he helped rebuild a Jewish school in the town, and when it moved to Naples he used whatever free time he had to set up a school for refugee children there.
All of which more than qualified Mr Ze'iri to go on to run a home for child Holocaust survivors on the edge of a small village in the Italian Alps.
The village is called Selvino and the official name of the home - a grand, multi-winged residence and former retreat for elite fascist youth - is Sciesopoli. But between 1945 and 1948, the 800 Jewish orphans who lived there would refer to it simply as "the house".
Two weeks ago, the village of Selvino marked the 70th anniversary since "the house" first opened its doors to the children. Local dignitaries came, including the mayor of Selvino, as did groups such as the National Association of the Italian Partisans, and the Union of Italian Jewish Communities. They were accompanied by scores of local children singing Hebrew songs and waving Israeli flags.
"They were very prepared for us," said Nitza Sarner, Mr Ze'iri's daughter.
"Us" was 12 of the "Selvino children", as the inhabitants of the former children's home are still known. Two had come from Canada, one from Florida and the remaining nine from Israel. Ms Sarner, who lived in the house with her parents from 1946 to 1948, now lives in Britain. If passionate Zionist Mr Ze'iri had had his way, they would have all flown in from Israel to mark the event. Deliberately isolated from local Italian life, the house at Selvino was a miniature Israel. The aim of the house, where Hebrew and Jewish history was taught daily, was not only emotional and physical rehabilitation: it was to prepare the children for life in the Promised Land. Ideally, on a kibbutz.
To this end, the house was run as a children's collective. The youngsters elected a work committee to organise the rotation of chores, an editorial board, which produced a weekly newspaper, and set up cultural and immigration committees.
However, there was a significant departure from kibbutz ideology. One person always had the final word: Mr Ze'iri.
As well as being house leader, Ms Sarner's father was a strict disciplinarian. Precisely because the children had been through a hell where all moral order had collapsed, he believed it vital that they now lived according to an ethical framework in which everyone worked for the common good. A child who damaged house property, for example, was punished with extra chores.
Although the children often resented his discipline, they were also, said Ms Sarner, deeply attached to the man they saw as their father.
